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Graphical method based on modified maximum force criterion to indicate forming limit curves of 22MnB5 boron steel sheets at elevated temperatures

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Journal of Iron and Steel Research International 2021年第8期28卷 1009-1018页

作者： Thanh Luyen quoc-Tuan pham Thi-Bich Mac Tien-Long Banh Duc-Toan nguyen Faculty of Mechanical Engineering Hungyen University of Technology and EducationHungyen 160000Vietnam Division of Computational Mathematics and Engineering Institute for Computational ScienceTon Duc Thang UniversityHo Chi Minh City 70000Vietnam Faculty of Civil Engineering Ton Duc Thang UniversityHo Chi Minh City 70000Vietnam School of Mechanical Engineering Hanoi University of Science and TechnologyHanoi City 100000Vietnam

A new approach for predicting forming limit curves(FLCs)at elevated temperatures was proposed *** are often used to predict failure and determine the optimal forming parameters of automotive ***,a graphical method based on a modified maximum force criterion was applied to estimate the FLCs of 22MnB5 boron steel sheets at room temperature using various hardening ***,the predicted FLC data at room temperature were compared with corresponding data obtained from Nakazima's tests to obtain the best *** estimate the FLC at elevated temperatures,tensile tests were conducted at various temperatures to determine the ratios of equivalent fracture strains between the corresponding elevated temperatures and room *** at elevated temperatures could be established based on obtained ***,the predicted FLCs at elevated temperatures did not agree well with the corresponding FLC experimental data of Zhou et al.A new method was proposed herein to improve the prediction of FLCs at elevated *** FLC calculated at room tem-perature was utilized to predict the failure of Nakazima's samples via finite element *** on the simulation results at room temperature,the mathematical relationships between the equivalent ductile fracture strain versus stress triaxiality and strain ratio were established and then combined with ratios between elevated and room temperatures to calculate the FLCs at different *** predicted FLCs at elevated temperatures agree well with the corresponding experimental FLC data.

关键词： Forming limit curve Modified maximum force criterion Graphical method Hardening law Finite element method Boron steel sheet Elevated temperature

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Structural and luminescent properties of (Eu,Tb) pO_4·H_2O nanorods/nanowires prepared by microwave technique

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Journal of Rare Earths 2011年第12期29卷 1170-1173页

作者： nguyen Thanh Huong nguyen Duc Van Dinh Manh Tien Do Khanh Tung nguyen Thanh Binh Tran Kim Anh Le quoc Minh Institute of Materials Science Vietnam Academy of Science and Technology University of Engineering and Technology National University HanoiVietnam

Nanowires/nanorods of europium/terbium orthophosphate monohydrate with Eu^3＋ concentration of 6, 11, and 20 at.% were prepared by microwave synthesis method. The effects of Eu^3＋ doping concentration on structure, morphology and optical properties of nanomaterials were also investigated. The results showed that, for all studied Eu^3＋ doping concentrations, a single-crystalline phase of rhabdophane-type （Eu,Tb）pO4·H2O nanowires/nanorods was obtained by using microwave heating of an aqueous solution of terbium（Ⅲ） nitrate, europium（Ⅲ） nitrate and NH4H2pO4 with pH=2. The length and width of these nanowires/nanorods ranged from 150 to 300 nm and from 10 to 50 nm, respectively. The evidence of energy transfer from Tb^3＋ to Eu^3＋ due to the energy overlap between the donor Tb^3＋ and the acceptor Eu^3＋was observed obviously via a significant enhancement in the luminescent intensity of Eu^3＋. Keywords：

关键词： microwave technique nanowires/nanorods energy transfer fluorescence spectroscopy rare earths

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Novel Deletion in Exon 7 of Betaine Aldehyde Dehydrogenase 2(BADH2)

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Rice science 2023年第2期30卷 104-112,I0020-I0030页

作者： VAN quoc Giang HUYNH Ky nguyen Chau Thanh Tung nguyen Loc Hien nguyen van Manh nguyen Nhut Thanh VO Cong Thanh SWEE Keong Yeap College of Agriculture Can Tho UniversityCan Tho 92000Vietnam Department of Sciences and Technology of Long An province Long An 850000Vietnam China-Association of Southeast Asian Nations College of Marine Sciences Xiamen University MalaysiaSepang 49000SelangorMalaysia

The fragrance of rice is one of the premium characteristics that breeders want to include in rice varieties due to the higher market value. Nucleotide deletions in exons 2(7 bp) and 7(8 bp) of Betaine Aldehyde Dehydrogenase 2(BADH2) are associated with fragrance in rice. In this study, a new 13 bp deletion in exon 7 of the BADH2 gene was discovered in the Nang Thom Cho Dao(NTCD) variety, and the mutation has been closely related to the genetic background of indica subspecies through the Bayesian phylogenetic approach and haplotype network analysis of the 3 000 Rice Genomes project. In addition, a set of functional markers(EX07-13F, EX07-13RN, and EX07-13RM) identified the 13 bp deletion only within NTCD(no amplified band) compared with both non-aromatic and other aromatic rice varieties(110 bp band). The deletion of 13 bases instead of 8 bases in exon 7 of BADH2 caused a premature stop codon, which down-regulated the expression of the BADH2 transcript while associated with up-regulation of Osp5CS and the high amount of 2-acetyl-1-pyrroline. It is potential to use the deletion in exon 7 of the BADH2 gene as a novel marker for adulteration and breeding of fragrant rice varieties, particularly for NTCD.

关键词： novel deletion BADH2 fragrant rice functional marker

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Spatial prediction of rainfall-induced shallow landslides using hybrid integration approach of Least-Squares Support Vector Machines and differential evolution optimization:a case study in Central Vietnam

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International Journal of Digital Earth 2016年第11期9卷 1077-1097页

作者： Dieu Tien Bui Binh Thai pham quoc phi nguyen Nhat-Duc Hoang Geographic Information System Group Department of Business Administration and Computer ScienceUniversity College of Southeast NorwayBøi TelemarkNorway Faculty of Geomatics and Land Administration Hanoi University of Mining and GeologyHanoiVietnam Department of Civil Engineering Gujarat Technological UniversityAhmedabadGujaratIndia Department of Geotechnical Engineering University of Transport TechnologyHa NoiVietNam Department of Environmental Sciences Hanoi University of Mining and GeologyHanoiVietnam Faculty of Civil Engineering Institute of Research and DevelopmentDuy Tan UniversityDanangVietnam

This study represents a hybrid intelligence approach based on the differential evolution optimization and Least-Squares Support Vector Machines for shallow landslide prediction,named as *** LSSVM is used to establish a landslide prediction model whereas the DE is adopted to search the optimal tuning parameters of the LSSVM *** this research,a GIS database with 129 historical landslide records in the Quy Hop area(Central Vietnam)has been collected to establish the hybrid *** receiver operating characteristic(ROC)curve and area under the curve(AUC)were used to assess the performance of the newly constructed *** results show that the proposed model has high performances with approximately 82%of AUCs on both training and validating *** model’s results were compared with those obtained from other methods,Support Vector Machines,Multilayer perceptron Neural Networks,and J48 Decision *** result comparison demonstrates that the DE-LSSVMSLp deems best suited for the dataset at hand;therefore,the proposed model can be a promising tool for spatial prediction of rainfall-induced shallow landslides for the study area.

关键词： Shallow landslide Least-Squares Support Vector Machines differential evolution GIS Vietnam

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A dual benchmarking study of facial forgery and facial forensics

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CAAI Transactions on Intelligence Technology 2024年第6期9卷 1377-1397页

作者： Minh Tam pham Thanh Trung Huynh Thanh Tam nguyen Thanh Toan nguyen Thanh Thi nguyen Jun Jo Hongzhi Yin quoc Viet Hung nguyen Griffith University Gold Coast CampusQueenslandAustralia Ecole polytechnique Federale de Lausanne VaudSwitzerland Faculty of Information Technology HUTECH UniversityHo Chi Minh CityVietnam Deakin University GeelongVictoriaAustralia The University of Queensland St LuciaQueenslandAustralia

In recent years,visual facial forgery has reached a level of sophistication that humans cannot identify fraud,which poses a significant threat to information security.A wide range of malicious applications have emerged,such as deepfake,fake news,defamation or blackmailing of celebrities,impersonation of politicians in political warfare,and the spreading of rumours to attract *** a result,a rich body of visual forensic techniques has been proposed in an attempt to stop this dangerous ***,there is no comprehensive,fair,and unified performance evaluation to enlighten the community on best performing *** authors present a systematic benchmark beyond traditional surveys that provides in-depth insights into facial forgery and facial forensics,grounding on robustness tests such as contrast,brightness,noise,resolution,missing information,and *** authors also provide a practical guideline of the benchmarking results,to determine the characteristics of the methods that serve as a comparative reference in this never-ending war between measures and *** authors’source code is open to the public.

关键词： benchmark deepfake digital forensics visual facial forgery

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Scale and scope economies in small household rice farming in Vietnam

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Journal of Integrative Agriculture 2021年第12期20卷 3339-3351页

作者： Viet-Ngu HOANG Trung Thanh nguyen Clevo WILSON Thong quoc HO Uttam KHANAL School of Economics and Finance Queensland University of TechnologyBrisbaneQLD 4000Australia Institute for Environmental Economics and World Trade Leibniz University HannoverHannover 30167Germany University of Economics Ho Chi Minh City Ho Chi Minh City 72516Vietnam Agriculture Victoria Department of JobsPrecincts and RegionsHorshamVIC 3400Australia

The Vietnamese agricultural sector has experienced a dramatic structural change based on increased specialization in rice ***,small-scale rice-farmers have continued to grow multiple crops,especially in less developed *** the literature advocates crop diversification for reasons of both economic and ecological sustainability,there lacks empirical evidence as to whether crop diversification brings efficiency and productivity gains to small *** present study is the first applications of the input-oriented stochastic distance function approach in estimating scale and scope economies using data of multi-crop farming households in *** find strong evidence of product-specific economies of *** economies are also present for rice,vegetable,and other annual crop *** suggests that crop diversification enhances efficiency and ***,there still exists significant technical inefficiency in crop production,indicating opportunities to expand farm output at the existing level of inputs and *** specifically,our empirical results indicate that it is desirable to expand vegetable and other annual crop production in mountainous areas while rice cultivation can be further expanded in delta and coastal regions.

关键词： input distance function stochastic frontier economies of scope economies of scale product-specific

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CONVERGENCE RESULTS FOR NON-OVERLAp SCHWARZ WAVEFORM RELAXATION ALGORITHM WITH CHANGING TRANSMISSION CONDITIONS

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Acta Mathematica Scientia 2022年第1期42卷 105-126页

作者： Minh-phuong TRAN Thanh-Nhan nguyen phuoc-Toan HUYNH Nhu-Binh LY Minh-Dang nguyen quoc-Anh HO Applied Analysis Research Group Faculty of Mathematics and StatisticsTon Duc Thang UniversityHo Chi Minh cityVietnam Department of Mathematics Ho Chi Minh City University of EducationHo Chi Minh cityVietnam Faculty of Mathematics and Statistics Ton Duc Thang UniversityHo Chi Minh cityVietnam

In this paper,we establish a new algorithm to the non-overlapping Schwarz domain decomposition methods with changing transmission conditions for solving one dimensional advection reaction diffusion *** precisely,we first describe the new algorithm and prove the convergence results under several natural assumptions on the sequences of parameters which determine the transmission *** we give a simple method to estimate the new value of parameters in each *** interesting advantage of our method is that one may update the better parameters in each iteration to save the computational cost for optimizing the parameters after many *** some numerical experiments are performed to show the behavior of the convergence rate for the new method.

关键词： domain decomposition method Schwarz waveform relaxation algorithm advection reaction diffusion changing transmission conditions

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Aerodynamic force generation of an insect-inspired flapper actuated by a compressed unimorph actuator

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Chinese Science Bulletin 2009年第16期54卷 2871-2879页

作者： nguyen quoc-Viet pARK Hoon C GOO Nam S BYUN Doyoung Department of Advanced Technology Fusion Konkuk University National Research Laboratory for Biomimetics and Intelligent Microsystems Konkuk University Department of Aerospace Engineering Konkuk University

We examined experimentally the flapping performance in terms of aerodynamic force generation of an insect-inspired flapper actuated by both of original LIpCA and compressed LIpCA. Flapping tests for two artificial wing shapes of horse botfly and hawk moth were conducted at the wing rotation angle of 60° and a flapping frequency range from 6 Hz to 12 Hz to find the optimum flapping frequency and to investigate the effect of compressed LIpCA and wing shape on the force generation. Flapping tests in the vacuum were also undertaken to measure the induced inertia force. The aerodynamic force was calculated by subtracting the inertia force from the total force measured in the air. It was found that the average inertia force was relatively small when compared with the average total force. The use of the compressed LIpCA could significantly improve the flapping angle of the flapper from 110° to 130° (18.2% increase) resulting in 24.5% increase in the average aerodynamic force. It was also found that flapper with hawk moth wings could produce larger force than the flapper with horse botfly wings.

关键词：空气动力驱动器插板压缩部队昆虫压电片单层

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A comparative analysis of weight-based machine learning methods for landslide susceptibility mapping in Ha Giang area

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Big Earth Data 2023年第4期7卷 1005-1034页

作者： Thanh Trinh Binh Thanh Luu Trang Ha Thi Le Duong Huy nguyen Trong Van Tran Thi Hai Van nguyen Khanh quoc nguyen Lien Thi nguyen Faculty of Computer Science Phenikaa UniversityYen NghiaHa DongHanoi 12116Vietnam phenikaa Research and Technology Institute(pRATI) A&A Green Phoenix Group JSCNo.167 Hoang NganTrung HoaCau GiayHanoi 11313Vietnam Northwestern Geological Division General Department of Geology and Minerals of VietnamHanoiVietnam Youth union office Thuyloi University175 Tay SonDong DaHanoiVietnam Center of Remote Sensing and Geohazards Vietnam Institute of Geosciences and Mineral ResourcesHanoiVietnam

Landslide susceptibility maps (LSMs) are very crucial for planningpolicies in hazardous areas. However, the accuracy and reliability ofLSMs depend on available data and the selection of suitable *** study is conducted to produce LSMs by combinations of machinelearning methods and weighting techniques for Ha Giang province,Vietnam, where has limited data. In study area, we gather 11 landslideconditioning factors and establish a landslide inventory *** the weights of classes (or factors) is very important toprepare data for machine learning methods to generate LSMs. Wefrst use frequency ratio (FR) and analytic hierarchy process (AHp)techniques to generate the weights. Then, random forest (RF), supportvector machine (SVM), logistic regression (LR), and AHp methods arecombined with FR and AHp weights to yield accurate and reliableLSMs. Finally, the performance of these methods is evaluated by fivestatistical metrics, ROC and R-index. The empirical results have shownthat RF is the best method in terms of R-index and the five metrics, *** rate (0.9661), Fp rate (0.0), ACC (0.9835), MAE (0.0046), and RMSE(0.0350) for this study area. This study opens the perspective of weightbasedmachine learning methods for landslide susceptibility mapping.

关键词： Landslide logistic regression random forest SvM Vietnam

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Local synthesis of carbon nanotubes for direct integration in Si microsystems——design considerations

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Advances in Manufacturing 2013年第3期1卷 218-225页

作者： Knut E.Aasmundtveit Bao quoc Ta quoc-Huy nguyen Tormod B.Haugen Nils Hoivik Einar Halvorsen IMST-Department of Micro and Nano System Technology HiVe-Vesffold University College

The integration of nanomaterials such as carbon nanotubes （CNTs） into microsystems is highly desirable, in order to make use of the unique nanomaterial properties in real devices. However, the CNTtomicrosystem integration is challenging to implement in a manufacturable, cost effective industrial process. This paper presents our work towards a process for making complete, integrated CMOS / MEMS systems with integrated CNT. We demonstrate the feasibility of the process, using roomtemperature process ing, lowcost equipment and consumables, and electrical control with automation possibilities. CNTs are directly integrated at the desired positions in the Si microsystem, forming closed Si / CNT / Si circuits. We explore different designs with the aim to obtain uniform and welldefined CNT synthesis conditions, and show that simplified designs can perform comparably to more complex ones. The Si / CNT / Si circuits obtained can show rectifying （Schottky like） or nearohmic behavior. Gas sensing possibilities are demonstrated, indicating the possibility of monitoring aging/ fermenting of food. Functionalization of CNTs is demon strated, using thermal evaporation of Sn and pd, opening for selective and sensitive sensors for various gases and ana lytes. Detailed microscopic characterization of the obtained CNTs are presented.

关键词： Micro/nano system integration Carbonnanotubes (CNTs) Nanoscale assembly - Gassensors

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